PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Learning Curve”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 667 records · Page 37Linked to original sources

[Laparoscopic transabdominal preperitoneal hernioplasty. Evaluation of complications due to transabdominal approach].

INTRODUCTION: Since the introduction of laparoscopic hernioplasty the TAPP procedure (transabdominal preperitoneal approach) has become the most widely used technique. Many surgeons have changed to the total extraperitoneal approach (TEP), because they fear the consequences of a peritoneal lesion. METHOD: We evaluated our results with TAPP in a retrospective study, with special attention to complications caused by the approach. We operated on 460 hernias in 390 patients in a period of 5 years. RESULTS: Complication rates and recurrence rates were similar to those after TEP. There was a marked learning curve with decrease of both rates during the evaluated years. There were no complications related to the transabdominal approach other than trocar hernias, the rate of which could be reduced by eliminating the learning curve and by using smaller trocar diameter. CONCLUSION: We see no reason to change from TAPP to the TEP technique.

Adult↗

The use of topographical landmarks to improve the outcome of Agee endoscopic carpal tunnel release.

A modified approach to endoscopic carpal tunnel release has been developed and tested in 60 cadaveric specimens by three surgeons using the Agee endoscopic carpal tunnel release system. The modified approach, which includes specific localization of the hook of the hamate, flexor retinaculum, and the superficial palmar arch utilizing topographical landmarks, avoids entry into Guyon's canal and injury to the ulnar artery and nerve, median nerve, and common digital nerves. Use of the anatomic approach resulted in significantly superior results. There were fewer incomplete releases, and fewer surgical passes were required, for the inexperienced surgeons. When these anatomic considerations were not included, the learning curve was much steeper. For surgeons planning endoscopic surgical release of the transverse carpal ligament, the described topographical approach improves the technical competence with the procedure and reduces the number of complications and learning curve associated with new procedures. We recommend the use of topographical landmarks and other anatomic considerations during endoscopic carpal tunnel release.

Cadaver↗

Holmium Laser Enucleation of the Prostate (HoLEP): A Technical Update.

INTRODUCTION: Holmium laser enucleation of the prostate (HoLEP) combined with mechanical morcellation represents the latest refinement of holmium:YAG surgical treatment for benign prostatic hyperplasia (BPH). Utilizing this technique, even the largest of glands can be effectively treated with minimal morbidity. The learning curve remains an obstacle, preventing more widespread adoption of this procedure. This paper provides an outline of the HoLEP technique as is currently used at two centers in hopes of easing the initial learning curve. TECHNICAL CONSIDERATIONS: Detailed descriptions of the major steps of the HoLEP procedure are provided with attention to critical steps such as identification of the surgical capsule, median and lateral lobe enucleation, and morcellation of enucleated tissue. CONCLUSIONS: HoLEP is a promising alternative for the surgical treatment of BPH which allows complete removal of intact lobes of the prostate. Obstruction is relieved immediately with superior hemostasis, no risk of TUR syndrome, and a minimal hospital stay.

Journal Article↗

Multiservice laparoscopic surgical training using the daVinci surgical system.

BACKGROUND: The daVinci surgical system affords surgeons a magnified three-dimensional videoscopic view of the operative field and precise articulating laparoscopic instruments. The learning curve for this advanced surgical robotics system is poorly characterized. METHODS: Twenty-three surgeons representing seven surgical subspecialties participated in a surgical robotics training program consisting of standardized daVinci system training (phase 1) followed by self-guided learning in a porcine model (phase 2). RESULTS: The average number of recorded procedures performed per surgeon during phase 2 was 5.5. The mean daVinci system set-up time was 45 minutes and decreased by an average of 56.1% by the third successive set-up (r = -0.702, P <0.005). Operative times decreased 39.0% by the third successive practice operation (r = -0.860, P <0.0005). CONCLUSIONS: New use of the daVinci robot is associated with a rapid learning curve and preclinical animal model training is effective in developing surgical robotics skills.

Animals↗

Prospective and comparative study of the anterolateral mini-invasive approach versus minimally invasive posterior approach for primary total hip replacement. Early results.

The interest in minimally invasive approaches for total hip replacement (THR) has not waned in any way. We carried out a prospective and comparative study in order to analyse the interest of the anterolateral minimal invasive (ALMI) approach in comparison with a minimally invasive posterior (MIP) approach. A group of 35 primary THRs with a large head using the ALMI approach was compared with a group of 43 THR performed through a MIP approach. The groups were not significantly different with respect to age, sex, bony mass index, ASA score, Charnley class, diagnoses and preoperative Womac index and PMA score. The preoperative Harris Hip Score was significantly lower in the ALMI group. The duration of surgical procedure was longer and the calculated blood loss more substantial in the ALMI group. The perioperative complications were significantly more frequent in this group, with four greater trochanter fractures, three false routes, one calcar fracture, and two metal back bascules versus one femoral fracture in MIP group. Other postoperative data (implant positioning, morphine consumption, length of hospital stay, type of discharge) are comparable, such as the early functional results. No other complication has been noted during the first 6 months. The ALMI approach uses the intermuscular interval between the tensor fascia lata and the gluteus medius. It leaves intact the abductor muscles, the posterior capsule and the short external rotators. The early clinical results are excellent, despite the initial complications related to the initial learning curve for this approach and the use of a large head. The stability and the absence of muscular damage should permit acceleration of the postoperative rehabilitation in parallel with less perioperative complications after the initial learning curve.

Adult↗

Percutaneous femoral puncture for endovascular treatment of occlusive arterial lesions.

BACKGROUND: Percutaneous femoral arterial access is a most important and difficult aspect of endovascular intervention, and the source of most complications. METHODS: A retrospective review was made of the authors' 9-year experience with 755 femoral punctures for the endovascular treatment of occlusive disease. The main focus was the evolving success rate with percutaneous arterial entry and the incidence of access-related complications. RESULTS: Cutdowns were frequent during the first 2 years, 54% and 17%, respectively, decreasing to 5% or lower by the third year. The incidence of femoral hematoma and other complications mirrored the same learning curve. After cutdown, wound infections and lymph leakage occurred in 2.4% each, and prolonged significant pain in 5%. CONCLUSIONS: Percutaneous puncture is a crucial skill in endovascular intervention. Practicing vascular surgeons can expect a significant learning curve. Performance can be optimized through intensive basic and advanced training and preceptorship. The cutdown approach is neither necessary nor acceptable for most endovascular procedures.

Arterial Occlusive Diseases↗

Introduction of sedative, analgesic, and neuromuscular blocking agent guidelines in a medical intensive care unit: physician and nurse adherence.

OBJECTIVE: To determine physician and nurse adherence with sedative, analgesic, and neuromuscular blocking agent guidelines in the management of mechanically ventilated patients in a medical intensive care unit. DESIGN: Prospective cohort study. SUBJECTS: One hundred consecutively admitted patients to a medical intensive care unit who required mechanical ventilatory support. A sample of 29 nurses, residents, and attending physicians were interviewed regarding their attitudes and perceptions of the guidelines. MEASUREMENT: Data were collected from concurrent medical records and included the following: demographic characteristics; clinical variables; physician prescriptions of sedative, analgesic, and/or neuromuscular blocking agents; nurse administration of these medications; documentation of monitoring; and assessment of patient hemodynamic status and behaviors. A semistructured interview was elicited from both nurses and physicians about their rationale for the use or nonuse of the guidelines. RESULTS: Patients ranged in age from 24 to 87 yrs, mean 60.7 (+15.3) yrs. Admission Acute Physiology and Chronic Health Evaluation III scores ranged from 36 to 192, mean 93.8 ( 30.5) and median 88. Length of mechanical ventilatory support ranged from 1 to 112 days, mean 14.8 ( 20.0) days, and median 8 days; medical intensive care unit length of stay ranged from 1 to 46 days, with a mean of 9.8 ( 8.1) days and a median of 8 days. Of the 100 patients, 47% died, 28% returned home, and 25% were discharged to a nursing facility. Eighty-five patients were administered one or more sedative, analgesic, and/or neuromuscular blocking agent, range 1-9 drugs, mean 2.5 (+1.5) drugs. Physicians prescribed 14 different medications; the most commonly administered drug was lorazepam (n = 71), followed by morphine (n = 39). Physicians and nurses had partial or total adherence to the guidelines in 58% of patients. The initial choice of the drug followed the guidelines in 60% of patients; the overall guideline was followed in 23% of patients. The most common rationales for nonadherence to the guidelines stated by both physicians and nurses were patient-specific factors, resident guideline learning curve, and physician medication preferences. CONCLUSION: Most patients required treatment for agitated behaviors. The majority of treatment regimens partially or totally adhered to the guidelines. Factors such as patient-specific disease states, resident guideline learning curve, and physician preferences of medications may have decreased adherence. Improving adherence to the guidelines is essential to assess their effectiveness in improving clinical outcomes.

Adult↗

Impact of educational intervention on confidence and competence in the performance of a simple surgical task.

BACKGROUND: Many complex new procedures involve a learning curve, and patients treated by individuals who are new to a procedure may have more complications than those treated by a practitioner who has performed the intervention more frequently. Still, at some point on the learning curve, each individual must decide that he or she is qualified to perform a procedure, presumably on the basis of his or her level of confidence, background, education, and skill. To evaluate the interrelationship of these factors, we designed a study in which we assessed the performance of a simulated knee joint injection. METHODS: Ninety-three practitioners attending a continuing medical education session on knee injection were randomized to receive skills instruction through the use of a printed manual, a video, or hands-on instruction; each performed one injection before and after instruction. The participants completed pre-instruction and post-instruction questionnaires gauging confidence and also provided self-assessments of their performances of injections before and after instruction. Self-assessments were compared with objective performance standards measured by custom-designed knee models with electronic sensors that detected correct needle placement. RESULTS: Before instruction, the participants' confidence was significantly but inversely related to competent performance (r = -0.253, p = 0.02); that is, greater confidence correlated with poorer performance. Both men and physician-practitioners displayed higher pre-instruction confidence (p < 0.01), which was not correlated with better performance. After instruction, performance improved significantly in all three training groups (p < 0.001), with no significant differences in efficacy detected among the three groups (p = 0.99). After instruction, confidence correlated with objective competence in all groups (r = 0.24, p = 0.04); however, this correlation was weaker than the correlation between the participants' confidence and their self-assessment of performance (r = 0.72, p = 0.001). CONCLUSIONS: Even low-intensity forms of instruction improve individuals' confidence, competence, and self-assessment of their skill in performing the fairly straightforward psychomotor task of simulated knee injection. However, men and physicians disproportionately overestimated their skills both before and after training, a finding that worsened as confidence increased. The inverse relationship between confidence and competence that we observed before the educational intervention as well as the demographic differences that we noted should raise questions about how complex new procedures should be introduced and when self-trained practitioners should begin to perform them.

Clinical Competence↗

Assessment of technical competence during ERCP training.

BACKGROUND: Successful performance of diagnostic and therapeutic ERCP requires skillful manipulation of the duodenoscope and accessories. The evaluation process for assessing competency is still in evolution. Recommendations for the number of examinations has ranged from 35 to 200, made without the benefit of prospective data. METHODS: Pancreatic and common bile duct cannulation rates were prospectively recorded for 21 trainees and 9 proctors over 6 years in a large university-based training program. Trainee success rates were compared to those of the proctor and learning curves were constructed. RESULTS: Trainees performed 641 examinations over 6 years. Each did an average of 31 examinations (range, 10 to 96). For both pancreatic duct and common bile duct cannulation, there was a rapid linear rise of the success curve extending up to the fortieth procedure. Pancreatic duct cannulation rates exceeded those of the common bile duct. CONCLUSIONS: This is the first prospective evaluation of acquisition of skills in ERCP. Although the rapid rise of the learning curve ends at the fortieth examination, the 85% level of selective cannulation is not reached for the pancreas duct until the seventieth procedure and is not reached for the common bile duct even at 100 procedures. These data suggest a threshold of at least 100 procedures.

Biliary Tract Diseases↗

Reduced postoperative morbidity after elective laparoscopic cholecystectomy: stratified matched case-control study.

To answer the question whether laparoscopic cholecystectomy (LC) or open cholecystectomy (OC) is safer in terms of complications and to what extent the "learning curve" influences the frequency of complications after LC, we conducted a matched case-control study. First, 200 patients undergoing LC (LC group A), and two groups of 200 patients undergoing LC at two different periods of the learning curve (LC groups B and C) were matched, taking into account sex, age, anesthesiologic risk, and surgical difficulties. We evaluated the frequency and grade of postoperative complications of these patients and of the last 200 patients undergoing OC before the introduction of LC, retrospectively matched with the LC groups. The total rate of complications in the OC group was 16.0% compared with 5.5% in the LC groups (p < 0.003); the difference was particularly significant for complications classified as grade I, in female patients, those younger than 70, those with low anesthesiologic risk (ASA), and those after cholecystectomy without surgical difficulties. Matched case-control analysis revealed that the complication rate in the LC group significantly decreases with experience (P < 0.01). We conclude that LC is today the treatment of choice for symptomatic cholelithiasis and is replacing OC as the gold standard against which new therapies should be compared.

Adult↗

[Arthroscopic treatment of dorsal ganglion cyst at the wrist. About 54 cases].

INTRODUCTION: Ganglion cyst of the wrist can, some time, need surgery. Different arthroscopic technical procedures have been described. We report our experience in all articular resection of dorsal ganglion cyst of the wrist. OBJECTIVES: Evaluation of efficiency of resection of dorsal ganglion cyst of the wrist by of arthroscopic resection of the pedicle. METHODS: Fifty-four cysts of 52 patients have been evaluated retrospectively. Operative data, pain, strength, recurrence and complications have been collected. RESULTS: Average follow up was 28 months (6 to 78). Return to work was 8,8 days, operative time 41 minutes (25 to 90). In 67% cases, the operation was judged easy. Three surgeries had to be performed open. Complications were one hematoma and one neurodystrophy. Pain decrease from 3,37 to 1,76 on analogical pain scale. Flexion was 89% of opposite side, extension 88%. Sixteen recurrences (29.7%) were found. Sixty percent of those recurrences occurred during the first year experience. But independently of experience, the operative performance was foun difficult in 1 time on 3. CONCLUSION: Endoarticular arthroscopic resection of the pedicle of ganglion cyst is not so reproducible. In experimented hands, it remains a difficult procedure after a long learning curve with a recurrence rate 3 times higher from what is reported in literature for open surgery. For our discharge, our long follow-up can contain some cases of de novo cyst explaining this high rate, the learning curve is certainly the main reason for our high recurrence.

Adolescent↗

Teaching invasive perinatal procedures: assessment of a high fidelity simulator-based curriculum.

OBJECTIVE: Learning curves pose a difficult problem in the teaching of technical skills: how do you teach procedural skills without compromising patients' health? A simulator-based curriculum has been designed to minimize the risks to patients undergoing amniocentesis by shifting the learning curve away from patients and into the laboratory. This study evaluated the effectiveness of a high-fidelity simulator-based curriculum in improving the performance of amniocentesis by obstetric trainees. DESIGN: Thirty trainees received a course on the practice of amniocentesis. The curriculum consisted of a lecture, a syllabus, and a hands-on training session with the simulator. Pre- and post-training performance were evaluated with two rating scales. Training and performance evaluation were completed using the same simulator. The effectiveness of the simulator-based workshop and the effect of year of training were assessed using a two-way analysis of variance. RESULTS: Performance scores improved from a mean score of 55% to 94% using checklist scoring and from 57% to 88% using global ratings. The two-way analysis of variance revealed a significant effect of training (F1,60 = 43.57; P < 0.001) accounting for 45% of the variance in scores, and a significant effect of experience level (F2,60 = 9.16; P < 0.001) accounting for 25% of the variance in scores. CONCLUSIONS: A comprehensive curriculum based on a high-fidelity simulator was effective at improving skills demonstrated on the simulator. The challenge remains to establish that skills acquired on a simulator are transferable to the clinical setting.

Amniocentesis↗

Statistical mechanics of learning with soft margin classifiers.

We study the typical learning properties of the recently introduced soft margin classifiers (SMCs), learning realizable and unrealizable tasks, with the tools of statistical mechanics. We derive analytically the behavior of the learning curves in the regime of very large training sets. We obtain exponential and power laws for the decay of the generalization error towards the asymptotic value, depending on the task and on general characteristics of the distribution of stabilities of the patterns to be learned. The optimal learning curves of the SMCs, which give the minimal generalization error, are obtained by tuning the coefficient controlling the trade-off between the error and the regularization terms in the cost function. If the task is realizable by the SMC, the optimal performance is better than that of a hard margin support vector machine and is very close to that of a Bayesian classifier.

Algorithms↗

Learning and generalization in radial basis function networks.

The two-layer radial basis function network, with fixed centers of the basis functions, is analyzed within a stochastic training paradigm. Various definitions of generalization error are considered, and two such definitions are employed in deriving generic learning curves and generalization properties, both with and without a weight decay term. The generalization error is shown analytically to be related to the evidence and, via the evidence, to the prediction error and free energy. The generalization behavior is explored; the generic learning curve is found to be inversely proportional to the number of training pairs presented. Optimization of training is considered by minimizing the generalization error with respect to the free parameters of the training algorithms. Finally, the effect of the joint activations between hidden-layer units is examined and shown to speed training.

Artificial Intelligence↗

Computer-assisted thoracic pedicle screw placement: an in vitro feasibility study.

STUDY DESIGN: In this cadaveric study, a computer-assisted image guidance system was tested for accuracy of thoracic pedicle screw placement. OBJECTIVES: Evaluate the system's accuracy for thoracic pedicle screw placement in vitro. SUMMARY OF BACKGROUND DATA: The effective use and reliability of pedicle screw instrumentation in providing short-segment stabilization and correction of deformity is well known in the lumbar spine. Pedicle screw placement in the thoracic spine is difficult because of the small dimensions of the thoracic pedicles and risk to the adjacent spinal cord and neurovascular structures. Investigators have shown the improved accuracy of computer-assisted lumbar pedicle screw placement; but the accuracy of computer-assisted thoracic pedicle screw placement, which is becoming more widely used, has not been shown. METHODS: In five human cadavers, 120 thoracic pedicle screws were placed with computer-assisted image guidance. The largest clinically feasible screw was used based on the cross-sectional dimensions of each pedicle. The accuracy was assessed by postoperative computed tomography and visual inspection. RESULTS: The overall pedicle cortex violation was 23 of 120 pedicles (19.2%). Nine violations (7.5%) were graded as major and 14 (11.7%) as minor. A marked and progressive learning curve was evident with the perforation rates that decreased from 37.5% in the first cadaver to 4.2% in the last two cadavers. CONCLUSIONS: Accurate thoracic pedicle screw placement is feasible with computer-assisted surgery. However, as with any other new surgical technology, the learning curve must be recognized and incorporated into the necessary fundamental knowledge and experience for these procedures.

Bone Screws↗

HIV disease management: new technologies improve outcomes and contain costs.

HIV disease presents a continuous learning curve as we move from managing a fatal illness to treating a chronic disease. Even though the HIV epidemic is more than 20 years old, our understanding of the disease and its management are constantly evolving. New technologies are an important part of this learning curve. As they are introduced, providers and managed care organizations need to develop policies and procedures that reflect the state of the art in HIV care to continue to build on the good outcomes seen since the advent of HAART. While this model of care is "expensive," it is less expensive long-term than the poorer outcomes and costs associated with increased hospitalization, drug resistance, and preventable morbidity in HIV disease.

Anti-HIV Agents↗

[Radical prostatectomy: open or "minimally invasive"? Our experience with open surgery and related comments].

Radical prostatectomy remains the gold standard for treatment of localised prostate cancer. Standardisation of the open retro-pubic anatomic prostatectomy by P Walsh allows skilled but not expert surgeons to achieve a high standard of performance. Learning curve is short with this technic, with minor morbidity. Rates of incontinence are low and impotency is now rather uncommon in the younger patient while oncological control is optimal for histologicaly organ confined cancer. "Mini invasive technics", laparoscopy and robot-assisted laparoscopy, have a longer learning curve, including a higher rate of complications that are unusual with open surgery. Operating time remains longer, costs are superior to the open technic and oncological control is not yet clearly validated while rates of classical late complications are not lower. Consequently, most urologist still prefer the open approach

Cost Control↗

Complications in transoral CO2 laser surgery for carcinoma of the larynx and hypopharynx.

BACKGROUND: Because of the increase in indications for laser surgery to treat malignant tumors of the larynx and hypopharynx, a higher number of complications may be expected. We prospectively evaluated the frequency and characteristics of intraoperative and postoperative complications of early and advanced tumors of the larynx and hypopharynx treated with CO(2) laser surgery and the potential influence of the surgical learning curve on the complication rate. METHODS: Two hundred seventy-five patients operated in a tertiary referral center. Complications were classified either as major, requiring intensive medical treatment, blood transfusion, surgery, or ICU admission, or minor, resolving spontaneously or with conventional ambulatory treatment without sequelae. The surgical learning curve was analyzed by dividing the patients into two groups according to the date of surgery and then comparing the number of complications. RESULTS: Complications occurred in 18.9% of patients; 9.8% were considered major and 9.1% minor. Complications included local infection (0.7%), emphysema (1%), cutaneous fistula (0.3%), postoperative bleeding (8%), airway ignition (0.3%), dyspnea (because of edema or stenosis) (1.8%), and swallowing difficulties or aspiration pneumonia (6.1%). The complication rate correlated significantly with tumor extension (p <.0001), the presence of diabetes mellitus (p =.01), and less surgical experience (p <.0001). Complications with severe sequelae occurred in two patients (p =.7). CONCLUSIONS: Complications after transoral laser surgery of larynx and hypopharynx carcinomas are relatively frequent (18.9%), but serious sequelae and mortality rate are low. Complications are associated with tumor extension, limited surgical experience, and diabetes mellitus.

Adult↗